# NASA - Looking Down a Well- A Brief History of Geodesy Cj1vgmXr5M

Geodesy is a field of study that deals with the measurement and representation of the Earth, and it all started when a clever human named Eratosthenes discovered that you could measure the circumference of the Earth by looking down a well. Over time, the field of geodesy has expanded and evolved dramatically, and NASA uses technology like radio telescopes, ground surveys, and satellites to contribute! Learn more about geodesy in this video! \r

\r This video is public domain and can be downloaded at: http://svs.gsfc.nasa.gov/goto?10910\r \r Like our videos? Subscribe to NASA's Goddard Shorts HD podcast:\r http://svs.gsfc.nasa.gov/vis/iTunes/f0004_index.html\r \r Or find NASA Goddard Space Flight Center on Facebook:\r http://www.facebook.com/NASA.GSFC\r \r Or find us on Twitter:\r

https://twitter.com/NASAGoddard

- Kind: Short
- Year: 2012
- Runtime: 2 min
- By: NASA Goddard
- Genres: Space, History
- Archive: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:NASA_-_Looking_Down_a_Well-_A_Brief_History_of_Geodesy_Cj1vgmXr5M.webm)
- Licence or status: Public domain (as the archive states it)
- Credit: NASA Goddard
- Who can watch: Tweens profiles and older (the archive gives no rating; placed by Invisible Network from its collection and subjects)

[Watch now](https://invisiblenetwork.ai/watch/archive/commons/96293776?play=1)